Graffiti of the fictional character Slender Man drawn on a street in Raleigh, N.C. / mdl70/Wikipedia

by Greg Toppo, USATODAY

by Greg Toppo, USATODAY

Can a quest for the approval of a fictional character turn an otherwise sane person into a murderer?

The arrest this week of two 12-year-old girls in Wisconsin in the attempted stabbing death of a classmate has focused attention on the role media play in violent crimes. Over the weekend, police in Waukesha County, Wis., say two girls lured a third into the woods after a sleepover and stabbed her 19 times, leaving her for dead. A passing bicyclist found the victim and called 911. She was reported in fair condition in an area hospital Thursday.

According to a criminal complaint filed in the attack, the girls were trying to become "proxies" of a fictional paranormal character called Slender Man, who first appeared online in 2009. The girls claimed that if they killed their friend they could prove themselves worthy to the character, who they believe is real. Police picked up the two Saturday as they walked from the crime scene toward a national forest in northern Wisconsin, where they allegedly believed Slender Man had a mansion. One of the girls carried a knife with a 5-inch blade in her backpack.

The two girls could face 65 years in prison if convicted of attempted homicide. USA TODAY is not naming the suspects because at least one of them is seeking to move the case into juvenile court. The 12-year-old girl who police say was repeatedly stabbed has been walking hospital halls with her father and watching TV in her wheelchair, according to her family.

Since artist Eric Knudsen posted the first Slender Man stories and photos in an online forum, hundreds of other writers, artists and programmers have created horror stories, films and video games featuring the tall, thin, faceless man in a black suit. Knudsen said in a statement that he was "deeply saddened by the tragedy in Wisconsin, and my heart goes out to the families of those affected by this terrible act."

David Morales, an administrator for creepypasta.wikia.com, a website that collects works related to Knudsen's character, said it had been overwhelmed by calls and messages since the stabbings. The site clearly states that the stories are fiction, Morales said, and that its rules bar use by anyone younger than 13.

The website gets its name from the Internet slang term "copypasta," itself a variation of the term "copy and paste," for content that's copied repeatedly online. The website "Know Your Meme" defines copypasta as "any block of text that gets copied and pasted over and over again, typically disseminated by individuals through online discussion forums and social networking sites."

"Overall, the community has deep condolences to the family of the victim and all those who were involved," Morales wrote.

Slender Man fans defended the stories and the community that has gathered around them. Lisa Morton, vice president of the Horror Writers Association, said the genre "helps us to explore and understand our own fears."

The site earlier this week featured a posting that noted, "This wiki does not endorse or advocate for the killing, worship and otherwise replication of rituals of fictional works. There is a line of (sic) between fiction and reality, and it is up to you to realize where the line is. We are a literature site, not a crazy satanic cult."

Outrage over violent material in the media is nothing new, said Glenn Sparks of Purdue University's Brian Lamb School of Communication. But he said research into so-called "media effects" shows the difficulty of laying blame for a violent act on a violent movie, cartoon, TV show or video game.

It's much more complicated than that, he said.

"It's unlikely that any particular aggressive act had a single cause," he said. "Aggressive behavior happens for all kinds of reasons. Like any human behavior, it has complicated causes, and it's most often the case that there's more than one cause."

While consuming violent media can raise a person's risk of behaving aggressively, so can many other things, including drug use, a child's peers and the values with which he or she has been raised.

In a few well-known cases, people have developed "parasocial relationships" with fictional characters, believing the character knows them and cares about them, Sparks said. A prominent example dates back 40 years, when actor Robert Young portrayed a likable family doctor named Marcus Welby on TV. "A lot of people wrote to him and asked him for medical advice," Sparks said.

People â?? particularly young people â?? sometimes can become so smitten with a fictional character that they can't separate fantasy from reality, he said. "Most media-effects scholars, when they read about this case, were like me and said, 'This is not completely outside of the realm of things that can happen,' " Sparks said.

Different people often have different reactions to watching violence in a film. "When people are making a connection between some ingredient in the film and their own personal experience, that becomes a powerful dynamic for them," Sparks said. Someone who has experienced trauma in his or her real life may react differently from someone who hasn't. "The effect of that is either magnified or reduced, or eliminated in some cases, by many other factors that are operating in a person's environment," Sparks said.

So it's difficult, if not impossible, to draw a direct line between consuming media and stabbing a friend 19 times.

The older brother of one of the suspects told London's Daily Mail that his sister "loved the Slender Man stories, just anything a bit creepy. But I don't see why it changed from dream to reality." He described her as a "very quiet" girl who kept to herself, "but she was happy-go-lucky, so this is completely out of the blue."

He added, "I know she understood what she was doing because she is very intelligent, to the point where she lacks common sense. â?¦ But she is only a little girl, so I don't think she understood the ramifications of what she was doing."